MacBook to TV Display Issues

I've been trying to set up my MacBook Pro to connected to my friend's old television. I have a Mini-DisplayPort to VGA adaptor connected to my computer, and from that I have a VGA to RCA adaptor connected to the tv itself. However, this setup isn't producing the results I had hoped for: instead of a clear display, we get a constantly wavering, green-and-pink image of my desktop mirrored multiple times. Changing the display settings has done nothing but make the display more out-of-focus, until it becomes just a constant stream of coloured lines.

There's clearly something wrong here, but I am far from tech-savvy, so I have no idea where to start looking. Any advice would be very much appreciated.